A possible problem you both are experiencing is that most ISPs block the default HTTP port; 80. You would have to forward say a port like 8080 on the WAN side to port 80 on the LAN side of your networks. To access your site from the internet, you would need to get a dynamic DNS provider like no-ip.com or dyndns.com, or you can remember your IP if you want...but they change regularly since most ISPs don't provide their residential customers with a static IP. To view your site from the internet, you would have to type in either the IP with the socket address trailing on the end (1.1.1.1:8080) or if you had the dynamic DNS provider it would be the same with a slight change instead of using the IP (yoursubdomain.no-ip.org:8080) but it depends on what dynamic DNS provider you go with and how they let you set it up. I know no-ip.com will allow you to automatically forward HTTP requests on port 8080 and the user would never know but again, it depends on how you set it up.
